The queues and delays at these lights have been a longstanding topic of local conversation, and one raised at several of our public meetings.  The worsening problems are variously attributed to a) the opening of Westfield b) too much traffic on Scrubs Lane/Wood Lane and c) poor phasing of the traffic lights, allowing too few vehicles to make a left turn onto Wood Lane.

The StQW Neighbouirhood Forum has been pursuing the issue with Transport for London. It is this body, rather than either LBHF or RBKC, who control these lights.  Wood Lane/Scrubs Lane is a major through route (the A219).

We have received a detailed reply in response to requests that the phasing of the lights be checked.  This is copied below.  I have also met on site with one of Transport for London’s traffic engineers, at 8.30 in the morning.

On that particular morning the traffic was light and there were no queues.  Just as when one takes one’s car into the garage and it refuses to exhibit the symptoms that led to you to take it there.  Sods Law.

I explained to TfL’s engineer that many of the worst queues occur in the mid afternoon and early evening, as well as during the morning rush hour.  Corroboration was provided by our local butchers, who regularly watch the Barlby Road/St Quintin Avenue triangle become grid-locked and traffic taking 20 minutes or more to get through the lights,.

Transport for London have promised to

• send out another engineer to observe from mid afternoon
• recheck the phasing (reviewed and adjusted last year)
• assess whether the queues in Wood Lane are the real problem, allowing very few vehicles to exit North pole Road when the lights are green
• check on the number of reports of long delays sent in by bus drivers

TfL also point out that it is LBHF who are responsible for the physical design of the junction.  TfL deal with the sequencing of the lights.

The StQW Forum will be following up on these issues, and including in the neighbourhood plan any possible measures to of improve the traffic flow at this junction.  But the basic problem remains that too much development is being built on the LBHF side of the boundary with no plans to do anything radical in terms of road or rail improvements. Hence our local campaign for a new Overground station beneath the Westway elevated roundabout.

The letter from TfL is as follows.   If anyone wants to see the November 2012 traffic survey data, referred to in the letter, please email info@stqw.org

Dear Mr Peterson,

Thank you for your email and bringing your concerns to our attention

The junction of Wood Lane, Scrubs Lane and North Pole Road operates using a system called SCOOT, which uses sensors embedded in the road surface to detect traffic and automatically adjust signal timings according to the relative demands on each approach.  Resurfacing works earlier in the year had damaged the detectors, which meant the junction was not able to optimise and respond to the demands of traffic as it should.  This may have been the source of some of the difficulties recently experienced.  The detection has now been fixed, so the timings should be back to normal and we can now keep a close eye on the operation and accurately observe the issues you have described.

I will be visiting the site next week, now that the Easter holidays are finished, to watch the junction and see the problem for myself.  I do appreciate the concerns of the residents and we will take time to investigate.  If we can make any improvements or we feel that the balance between north-south movements and east-west movements is not correct, we will investigate what changes can be made.

If you think it would be useful I would be happy to meet you at the junction to discuss the issues.  Let me know if this interests you and we can make arrangements.

In the meantime, here follows an explanation of the way the junction operates now.

The junction operates in four stages:

Stage 2 is only triggered when northbound vehicles are detected waiting to turn right.  When Stage 2 is triggered the left turn from North Pole Road gets extra green time, which is why green time for this movement is intermittently shorter or longer.  Stage 2 is typically called on around 70% of opportunities between 7am to 10am.  If vehicles turn between gaps in the southbound traffic then Stage 2 isn’t triggered. 

The pedestrian movements occur in stage 4.  When no one presses the button for green man, the extra green time is given to the north-south stage.  During the period 7am to 10am the pedestrian stage runs on approximately 40% of opportunities.  When the pedestrian stage is called, the necessary safety period between the end of green man to the start of north-south traffic green is 16 seconds long, during which time no traffic or pedestrians are given a green signal.  Although it may appear to the driver that this is wasted time, it is the necessary period to ensure no conflict between vehicles and people.

As mentioned before, the junction timings constantly optimise according to the demands of traffic from all approaches.  This means that I can’t quote fixed green times, but the table below gives typical green times for the AM peak hour between 8am and 9am.  Actual green times will differ considerably minute by minute as the junction optimises and when stages are not called by the right turn and pedestrians.

At the bottom of your email in point b you ask for traffic survey data which I have attached.  The most recent data we have dates from November 2012.  We don’t have any delay survey information for the junction.

Comparing crude, automatically collected flows for 2012 and 2013, there was a 2.3% increase in traffic flow at the junction.  This echoes a general trend of increased traffic levels across London over the last year.

In response to point c in your email, TfL have no proposals for a scheme that would reduce traffic levels that use this junction now or in the future.  As for mitigation, TfL will be assessing the impacts of the developments mentioned and will make decisions on what needs mitigating and how based on these predictions.

Please also bear in mind that, whilst TfL manages the traffic signals on Wood Lane, the decision to modify the physical design is the responsibility of LBH&F as this is a Borough-controlled road.